Numerous analog applications exist requiring high voltage tolerance, e.g., amplifier applications and flash memory to name but two.
In designing devices for use in high voltage applications, cross-talk between the devices is a common concern, one solution to dealing with this being the use of isolation regions between devices, as is realized in SOI processes.
Furthermore, whenever designing any additional protection feature it will be appreciated that it is highly desirable not to have to add additional process steps in order to achieve the structure but to be able to make use of existing process steps that are required in any event for forming other structures in the circuit. Such devices that require no additional process steps are commonly referred to as free devices.
The present invention seeks to provide a free ESD protection device with high voltage tolerance, implemented in a SOI process.